JP2005154771A - Method for forming semiconductor interlayer insulating film using molecular polyhedral silsesquioxane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a semiconductor interlayer insulating film capable of obtaining a low dielectric constant and inducing mechanical properties, thermal stability, resistance to cracking, and the like.
After producing a composition for forming an insulating film using molecular polyhedral silsesquioxane as a monomer of a siloxane resin, or using molecular polyhedral silsesquioxane itself as a pore-forming substance, An insulating film is formed using this.
[Selection] Figure 2

Description

  The present invention relates to a method for forming a semiconductor interlayer insulating film using molecular polyhedral silsesquioxane, more specifically, using the molecular polyhedral silsesquioxane of the present invention as a monomer of a siloxane resin, Alternatively, the present invention relates to a method for forming an insulating film by using a molecular polyhedral silsesquioxane itself as a pore-forming substance and producing an insulating film-forming composition. When the method of the present invention is used, the molecular polyhedral silsesquioxane itself has internal pores, so that a low dielectric constant can be obtained and various reactive groups can be introduced. Characteristic can be induced.

As the degree of integration of the semiconductor increases, the performance of the device depends on the wiring speed. Therefore, in order to reduce the resistance and capacity in the wiring, the storage capacity of the interlayer insulating film must be reduced. Specifically, in Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4, SOD (Spin on Deposition) is possible instead of SiO ₂ having a dielectric constant of 4.00 using the existing CVD method. Polysilsesquioxane having a dielectric constant of about 2.5 to 3.1 is used. In this case, since the planarization characteristics are good, a spin coating method can be applied.

Hydrogen silsesquioxanes and methods for their production are known in the art. For example, Patent Document 1 is basically completely completed by a process including a step of hydrolyzing trichlorosilane in a hydrolysis medium containing benzenesulfonic acid hydrate and then washing the resin with water or aqueous sulfuric acid. A method for producing a condensed hydrogen resin is disclosed. Patent Document 5 discloses a method comprising a step of hydrolyzing hydrosilane to form a resin in a hydrolysis medium containing aryl sulfonic acid hydrate, and then contacting the resin with a neutralizing agent. Disclosure. Patent Document 6 discloses a silicon resin excellent in solution stability and solubility produced by subjecting tetraalkoxysilane, organic silane and organic trialkoxysilane as monomers to hydrolysis and condensation reaction in the presence of water and a catalyst. Disclosed are compositions and methods for making the same. Patent Document 7 discloses that a monomer selected from alkoxysilane, fluorine-containing alkoxysilane, and alkylalkoxysilane and titanium (Ti) or zirconium (in order to improve resistance to oxygen plasma and physical properties, and to form a thick thin film. A silica-based compound produced by reacting a Zr) alkoxide compound with water in the presence of a catalyst is disclosed. Patent Document 8 discloses a siloxane, silsesquioxane polymer produced by using a compound in which another element or a reactive group is substituted at the β position of an organosilane in order to increase the content of SiO _{2 in} a thin film, and this The thin film composition used is disclosed. Patent Document 9 discloses that a composition comprising a combination of various alkoxysilane compounds such as monoalkoxysilane, dialkoxysilane, trialkoxysilane, tetraalkoxysilane and trialkoxysilane dimer and an organic polymer is used as an insulating film. doing.

  In order to lower the dielectric constant of the semiconductor interlayer insulating film to 2.5 or less, a porogen template is prepared by blending a pore-forming substance with the siloxane-based resin and thermally decomposing it in a temperature range of 250 ° C. to 350 ° C. (Porogen-template) method has been proposed. However, in such a method, as shown in FIG. 1, there is a problem that the pores collapse and are connected to each other when Si—OH is formed on the pore surface or the porogen is removed. This also reduces the adaptability of the porous insulating film having pores to the semiconductor insulating film.

  For example, a cage-type siloxane monomer represented by the following chemical formula 1 that has been studied conventionally has the following structure and a diagonal length of about 5.3 mm. When an insulating film is formed using this, a dielectric constant of 3.0 to 2.7 level is obtained. However, in order to lower the dielectric constant, the addition of porogen is indispensable. Problems arise.

US Pat. No. 3,615,272 US Pat. No. 4,399,266 US Pat. No. 4,756,977 US Pat. No. 4,999,397 US Pat. No. 5,010,159 US Pat. No. 6,232,424 US Pat. No. 6,000,339 US Pat. No. 5,853,808 European Patent Office Application No. 0997497A1 Specification

  Therefore, an object of the present invention is to solve such problems of the prior art.

  In the present invention, molecular polyhedral silsesquioxane having pores therein is used as a monomer of a siloxane resin used for the composition of the insulating film, or pore formation is performed during the formation of the insulating film composition. By using it as a material, a low dielectric constant can be realized, and various kinds of reactive groups can be introduced to introduce mechanical properties, thermal stability, resistance to cracking, etc. by the introduced functional groups. A forming method is provided.

  In order to achieve the above object, in one embodiment of the present invention, one or more molecular polyhedral silsesquioxanes represented by the following chemical formula 2 are used alone, or one or more silane-based monomers are used. And a siloxane-based resin produced by hydrolysis and condensation polymerization in the presence of water and an acid catalyst or a base catalyst in an organic solvent.

Wherein R is a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkynyl group, an aryl group or an alkoxy group, or -OSIR ₁ r ₂ r ₃ , r ₁ , r ₂ and r ₃ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkynyl group, an aryl group, or an alkoxy group, and the plurality of Rs are different from each other. And at least one of the R is a hydrolyzable functional group, and n is 10, 12, 14 or 16.)
In another aspect of the present invention, there is provided an insulating film forming composition comprising the produced siloxane-based resin and an organic solvent.

  In another aspect of the present invention, there is provided an insulating film forming composition comprising the molecular polyhedral silsesquioxane of Formula 2, a thermally stable siloxane precursor, and a solvent that dissolves the substance.

  In another aspect of the present invention, there is provided a method for forming an insulating film comprising the step of applying the composition for forming an insulating film on a substrate and thermally curing the composition.

  In another aspect of the present invention, a semiconductor interlayer insulating film formed by the above method is provided.

The molecular polyhedral silsesquioxane according to the present invention is excellent in compatibility with existing siloxane-based resins, and can be easily introduced with various derivatives. When forming a polymer, In the case of a film produced using this, the mechanical properties, thermal stability and resistance to cracking are excellent, and the carbon content is low, the SiO ₂ content is high, and the insulating properties are excellent. It can be usefully used in the semiconductor element field.

  Hereinafter, the present invention will be described in more detail.

  In the present invention, one or more kinds of molecular polyhedral silsesquioxanes represented by the following chemical formula 2 are directly used for polymerization of a siloxane-based resin used for forming an insulating film, or one of the compositions for forming an insulating film. It can be used as a substance for introducing pores as a component.

Wherein R is a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkynyl group, an aryl group or an alkoxy group, or -OSIR ₁ r ₂ r ₃ , r ₁ , r ₂ and r ₃ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkynyl group, an aryl group, or an alkoxy group, and the plurality of Rs are different from each other. And at least one of the R is a hydrolyzable functional group, and n is 10, 12, 14 or 16.)
Next, the process in which the molecular polyhedral silsesquioxane is used for the polymerization of a siloxane resin will be described in more detail. That is, the molecular polyhedral silsesquioxane of the chemical formula 2 is used alone or mixed with one or more silane monomers selected from the group consisting of compounds represented by the following chemical formulas 3 to 6. Then, a siloxane-based resin is produced by condensation polymerization in the presence of water and an acid catalyst or a base catalyst in an organic solvent.

(Wherein R ₁ is a hydrogen atom, a C ₁ -C ₃ alkyl group or a C ₆ -C ₁₅ aryl group, R ₂ is a hydrogen atom, a C ₁ -C ₁₀ alkyl group or SiX ₁ X ₂ X a _{3 (here,} a X _1, X 2, _{X 3} are each independently a hydrogen _atom, C 1 -C ₃ alkyl _group, an alkoxy group or a halogen atom C 1 _{-C 10,} at least one It is a hydrolyzable functional group), p is an integer of 3-8.)

(In the formula, R ₁ is a hydrogen atom, a C _{1 to} C ₃ alkyl group or a C _{6 to} C ₁₅ aryl group, and X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, C _{1 to} C 3 ₃ alkyl _group, an alkoxy group or a halogen atom C 1 _{-C 10,} at least one is a hydrolyzable functional group, m is an integer of 0, p is an integer of 3-8. )

(Wherein X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, a C _{1 to} C ₃ alkyl group, a C _{1 to} C ₁₀ alkoxy group or a halogen atom, at least one of which can be hydrolyzed) M is a direct bond or a C _{1 to} C ₁₀ alkylene group, or a C _{6 to} C ₁₅ arylene group.)

(In the formula, R ₁ is a hydrogen atom, a C ₁ -C ₃ alkyl group, a halogen group, or a C ₆ -C ₁₅ aryl group, and R ₂ is a hydrogen atom, a C ₁ -C ₃ alkyl group or C _6. an aryl group -C _15, at least one of _{R 1} and oR ₂ is a hydrolyzable functional group, n is an integer of 0 to 3.)
Examples of the basic structure of the specific compound of the molecular polyhedral silsesquioxane include a structure represented by the following chemical formula 7.

In the formula, various substituents can be bonded to the Si molecule. By changing the Si—H bond to Si—OH, Si—OR, Si—CH═CH ₂ or the like, a sol-gel reaction or a polymer polymerization reaction is possible. Each functional group of the compound has good compatibility with the siloxane resin, and can be used as an additive to utilize pores inside the molecular polyhedron type.

  Among the compounds, silsesquioxane in which a hydrogen atom is bonded to a Si atom has a body diagonal of the Si—O—Si skeleton having a length of about 8.3 mm. Can be lowered to 2.5 to 1.8. In the case where a polymer is produced using an oligomer in which a hydrogen atom is bonded to an oxygen atom facing the outside of the molecule in the structure as a starting monomer, and this is used to form an insulating film, this molecule Since all of the Si atoms have a Q structure, they have excellent mechanical properties such as elastic modulus and hardness, and have a low CTE (coefficient of thermal expansion).

Further, when the molecular polyhedral silsesquioxane having the structure as described above is used, an insulating film having a pore wall as shown in FIG. 2 can be manufactured. That is, a porous insulating film can be formed by introducing a spherical insulator having pores inside into the film. In this case, since the spherical insulator has a complete form in the molecule, there is a problem in the conventional technology that Si—OH is formed or the pores in the thin film are connected to each other due to aggregation of the pore-forming substances. Hard to do. In addition, when applied to a semiconductor process, molecules such as HF or H ₂ O that may be generated in the insulating film are difficult to enter inside the pores, so the process adaptability is dramatically improved and the entire pore volume is increased. Will increase. As a result, the dielectric constant can be lowered to 2.0 or less. In addition, although the dielectric constant is lowered by pore formation, it is not removed by heat unlike existing pore-forming substances, and therefore it is expected that the decrease in mechanical properties with respect to the dielectric constant is small.

  The molecular polyhedral silsesquioxane having various substituents used in the present invention is specifically produced by the route represented by the following reaction formula 1.

  In the present invention, preferably, as the molecular polyhedral silsesquioxane, a compound represented by the following chemical formula 8 is used alone, or selected from the group consisting of the compounds represented by the above chemical formulas 3, 4, 5 and 6. It is possible to produce a siloxane-based resin by mixing with one or more silane-based monomers and performing condensation polymerization in an organic solvent in the presence of water, an acid, a base, or a metal catalyst.

  In the production of the siloxane-based resin, when one or more silane-based monomers selected from the group consisting of molecular polyhedral silsesquioxane and a compound of Chemical Formulas 3-6 are polymerized, the reaction ratio is 9.999. : It is preferable that it is 0.001-0.001: 9.999.

  The acid, base or metal catalyst used in the production of the siloxane resin is hydrochloric acid, nitric acid, benzenesulfonic acid, oxalic acid, formic acid, potassium hydroxide, sodium hydroxide, triethylamine, sodium hydrogen carbonate, pyridine, and derivatives thereof. (For example, a Pt derivative or a Pd derivative) can be used. The catalyst is preferably used in a molar ratio of all monomers to the catalyst used of 1: 0.00001 to 1:10.

  The water used in the hydrolysis and condensation reaction preferably has a monomer to water molar ratio in the range of 1: 1 to 1: 100.

  The organic solvent is preferably an aliphatic hydrocarbon solvent such as hexane or heptane; an aromatic hydrocarbon solvent such as anisole, mesitylene, xylene, benzene; methyl isobutyl ketone, 1-methyl-2-pyrrolidinone, cyclohexanone, acetone, etc. Ketone solvents such as tetrahydrofuran and isopropyl ether; acetate solvents such as ethyl acetate, butyl acetate and propylene glycol methyl ether acetate; alcohol solvents such as isopropyl alcohol and butyl alcohol; dimethylacetamide and dimethylformamide It is preferable to use an amide solvent; a silicon solvent; or a mixture thereof.

  The hydrolysis and condensation reaction is more preferably performed at a temperature of 0 to 200 ° C. for 0.1 to 100 hours.

  The produced siloxane-based resin preferably has a weight average molecular weight of 1,000 to 300,000.

  The composition for forming an insulating film is manufactured by dissolving the siloxane-based resin obtained by the condensation polymerization in the exemplified organic solvent. At this time, a known pore-forming substance is added if necessary. Can do.

  On the other hand, the molecular polyhedral silsesquioxane represented by Chemical Formula 2 in the present invention acts as a pore-forming substance, and forms a porous insulating film forming composition together with a thermally stable siloxane precursor and a solvent for dissolving them. It can also be used for manufacturing. In this case, the molecular polyhedral silsesquioxane can act alone as a pore-forming substance, but can be used in combination with all known pore-forming substances.

  Preferable examples of the pore-forming substances used in combination include cyclodextrin, polycaprolactone, Brij surfactant, polyethylene glycol-polypropylene glycol-polyethylene glycol ternary block copolymer surfactant and derivatives thereof. Can be mentioned.

  In the composition for forming an insulating film, the molecular polyhedral silsesquioxane is preferably contained in an amount of 0.1 to 99.9% by mass with respect to the total solid content in the composition. In the composition for forming an insulating film, the pore-forming substance is preferably 0.1 to 99.9% by mass, based on the total weight of the solid content in the composition (that is, the siloxane precursor + the pore-forming substance). More preferably, it is present in an amount of 1 to 70% by weight, but is not limited thereto.

  When molecular polyhedral type silsesquioxane is used as a pore-forming substance, a siloxane monomer selected from the group consisting of chemical formulas 3 to 6 is formed as the thermally stable siloxane precursor. It can be manufactured and used in the same manner as the method. That is, as the thermally stable siloxane precursor, one or more monomers selected from the group consisting of compounds represented by the chemical formulas 3, 4, 5 and 6 are mixed, and water and acid are mixed in an organic solvent. A compound produced by condensation polymerization in the presence of a catalyst or a base catalyst may be used.

  The organic solvent that can be used at the time of producing the composition for forming an insulating film is not particularly limited, and all the organic solvents described above can be preferably used.

  The solid content in the composition is not particularly limited, but it is more preferable that the solid content is 5 to 70% by mass based on the total weight of the composition including the organic solvent and the solid content.

  An insulating film forming composition comprising a siloxane-based resin produced using the molecular polyhedral silsesquioxane produced above or an insulating film forming composition comprising a molecular polyhedral silsesquioxane as a pore-forming substance, The insulating film can be formed by curing after coating the substrate. The composition may include the aforementioned pore-forming substances such as cyclodextrin.

  The substrate is not particularly limited as long as it does not hinder the object of the present invention, and all substrates that can withstand thermosetting conditions, for example, a glass substrate, a silicon wafer, a plastic substrate, etc., can be selected and used depending on the application. it can. Examples of coating methods that can be used in the present invention include, but are not limited to, spin coating, dip coating, spray coating, flow coating or screen printing. The most preferable coating method in terms of convenience and uniformity is spin coating. When performing spin coating, the spin speed is preferably adjusted within a range of 800 to 5,000 rpm.

  After the coating is completed, the method includes a process of evaporating the solvent and drying the film, if necessary. The film drying process is preferably performed by simply exposing it to the surrounding environment, applying a vacuum at the initial stage of the curing process, or heating at a relatively low temperature of 200 ° C. or less.

  Next, the film is preferably thermoset at a temperature of 150 ° C. to 600 ° C., more preferably 200 ° C. to 450 ° C. for 1 to 180 minutes to form an insoluble film without cracks. “Crack-free coating” refers to a coating in which any cracks observed with the naked eye are not observed when observed with an optical microscope at 1000 magnifications. Insoluble coating refers to the formation of a film by depositing a siloxane polymer. A coating that is essentially insoluble in the solvent described as being useful for applying the solvent or resin. When pore-forming substances other than molecular polyhedral silsesquioxane are included, the thermosetting temperature is determined in consideration of the decomposition temperature of the pore-forming substances.

  The insulating film using the molecular polyhedral silsesquioxane has a dielectric constant of 3.0 or less depending on the content of the polyhedral material, and thus can be used as a low dielectric semiconductor interlayer insulating film. The insulating film produced according to the present invention is excellent in mechanical properties such as toughness and elasticity, and has a low carbon content in the film, so that it can be usefully used as a semiconductor interlayer insulating film.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, these examples are for explaining the present invention, and the present invention is not limited to the examples.

First, a method for measuring the performance of the insulating film manufactured in the following example will be described in detail.
(1) Dielectric constant measurement:
A silicon thermal oxide film was applied to a thickness of 3000 mm on a p-type silicon wafer doped with boron, and 100 mm of titanium, 2000 mm of aluminum, and 100 mm of titanium were deposited by a metal vapor deposition device. Thereafter, an insulating film to be measured was formed thereon. A low dielectric thin film for measuring the dielectric constant of MIM (metal-insulator-metal) structure by depositing 100 mm of circular titanium having a diameter of 1 mm and 5000 mm of aluminum using a hard mask designed to have an electrode diameter of 1 mm on the insulating film. Was completed. Measure the capacitance of the completed thin film using a PRECISION LCR METER (HP4284A) with a probe station (micromanipulator 6200 probe station) at frequencies of about 10 kHz, 100 kHz and 1 MHz, and measure the thickness of the thin film using a prism coupler. Then, the dielectric constant was obtained from Equation 1.

(Where k is the relative dielectric constant, C is the capacitance, ε ₀ is the vacuum dielectric constant (ε ₀ = 8.8542 × 10 ⁻¹² Fm ⁻¹ ), d is the thickness of the insulating film, and A is the electrode. (Contact cross-sectional area.)
(2) Hardness and modulus of elasticity:
The hardness and elastic modulus were determined by quantitatively analyzing the insulating film using Nano Indenter II manufactured by MTS. More specifically, the hardness and elastic modulus of the thin film were obtained when the thin film was press-fitted with a nanoindenter and the press-fitting depth was 10% of the thin film thickness. The thickness of the thin film was measured using a prism coupler. In this example, in order to ensure reliability, nine places on the insulating film were press-fitted and the respective hardness and elastic modulus were obtained from the average values.

(Manufacture of molecular polyhedral silsesquioxane)
Production Example 1
To the dried flask, 80 g of sulfuric acid (H ₂ SO ₄ ) and fuming sulfuric acid containing 15% SO ₃ were mixed well with 200 mL of benzene, and then 12.7 g (0.3. 094 mmol) was charged. When the addition of trichlorosilane was completed, the organic layer was washed several times with a 50% H ₂ SO ₄ solution and further washed with distilled water. In order to eliminate substances that are not dissolved in the organic layer and substances that are not removed, the organic layer is concentrated after filtering to obtain 4.8 g of a molecular polyhedral silsesquioxane precursor (n = 12, 14, 16) ( The chemical formula 8) was obtained. The mixture thus obtained was separated from each other by the sublimation method.

Production Example 2
1 g of [Si ₁₄ O ₂₁ ] H ₁₄ n = 14 obtained in Production Example 1 was charged into a flask, dissolved in 20 mL of methanol, 0.1 g of Pd / C was charged and reacted at room temperature for 8 hours. ₁₄ O ₂₁ ] OMe ₁₄ 0.8 g was obtained.

(Production of polymer containing molecular polyhedral silsesquioxane)
Production Example 3
After charging 5 g of the monomer [Si ₁₄ O ₂₁ ] H ₁₄ obtained in Preparation Example 1 into a flask and diluting with benzene so that the concentration of the whole solution becomes 0.05 to 0.07M, It was added 0.01 mmol% of PtCl ₂ catalyst the flask was then 12 hours at room temperature. After the reaction was completed, the catalyst was removed from the solution using celite, which was filtered through a filter having a pore size of 0.2 μm, and then the solvent was removed. The white powder was dried at a temperature of 0 to 20 ° C. and a pressure of 0.9 torr for 4 hours to obtain 3.5 g of a siloxane polymer “hereinafter referred to as“ (a-1) ””. The Si—OH content and Si—CH ₃ content in the polymer were 38.70% and 61.30%, respectively.

Production Example 4
The reaction was conducted at room temperature for 6 hours in the same manner as in Production Example 3 except that tetrahydrofuran was used instead of benzene as the solvent, and then 2,4,6,8-tetramethyl-2,4,6,8- Tetrakis (trimethoxysilyl) cyclosiloxane (5 g) was charged into a flask, and the temperature of the reaction solution was -78 ° C. After adding 0.484 mmol of hydrochloric acid and 241.2 mmol of water to the flask, the temperature of the reaction solution was gradually raised from −78 ° C. to 70 ° C. and reacted for 6 hours. After transferring the reaction solution to a separatory funnel, add the same amount of diethyl ether and tetrahydrofuran as the initially charged tetrahydrofuran, wash it out with about 1/8 of the total water, and remove volatile substances under reduced pressure. As a result, a white powder type polymer was obtained. The polymer obtained by the above method was dissolved in tetrahydrofuran to prepare a transparent solution, which was filtered through a filter having a pore size of 0.2 μm, and then water was gradually added to the filtrate to obtain a white powder precipitate. The white powder was dried at a temperature of 0 to 20 ° C. and a pressure of 0.9 torr for 8 hours to obtain 6.2 g of a siloxane polymer (hereinafter referred to as “a-2”). The Si-OH content and Si-OCH ₃ content and Si-CH ₃ respectively content 39.50% in the polymer, was 0.65% and 59.85%.

Production Example 5
2,4,6,8-Tetramethyl-2,4,6,8-tetrakis (trimethoxysilyl) cyclosiloxane (T4Q4) and methyltrimethoxysilane as acyclic alkoxysilane monomer (MTMS, manufactured by Aaldrich) ) Was used to produce a polymer (hereinafter referred to as “(a-3)”) in the same manner as in Production Example 4. Table 1 shows the amount of each monomer used in the production of the polymer and the amounts of HCl and water used. On the other hand, the amount of polymer obtained, the Si—OH content, the Si—OCH ₃ content, and the Si—CH ₃ content are also shown in Table 1.

Example 1
Using 0.207 g of the polymer (a-3) as the siloxane polymer, 0.046 g of the molecular polyhedral silsesquioxane (n = 14) of Production Example 1 as the pore-forming substance, and propylene glycol methyl ether as the solvent A coating solution having a solid content of 24% by mass was prepared using acetate. The coating solution was spin-coated on a silicon wafer at 2000 rpm for 30 seconds, and dried by preheating at 150 ° C. for 1 minute and at 250 ° C. for 1 minute on a hot plate in a nitrogen atmosphere. The film was heat-treated at 420 ° C. (temperature increase rate: 3 ° C./min) for 1 hour in a vacuum atmosphere to produce an insulating film C-1. The thickness, refractive index, dielectric constant, hardness, elastic modulus and carbon content of the manufactured insulating film were measured. The results are shown in Table 2.

Example 2
Except that 0.459 g of the polymer (a-3) was not used as a siloxane polymer, and a coating liquid having a solid content of 24% by mass was produced using propylene glycol methyl ether acetate as a solvent. An insulating film (C-2) was manufactured in the same manner as in Example 1. The thickness, refractive index, dielectric constant, hardness, elastic modulus and carbon content of the manufactured insulating film were measured. The results are shown in Table 2.

Example 3
Example 1 except that 0.413 g of the polymer (a-3) was used as the siloxane polymer and 0.046 g of heptakis [2,3,6-tri-methoxy] -β-cyclodextrin was used as the pore-forming substance. Insulating film (C-3) was produced in the same manner as in Example 1. The thickness, refractive index, dielectric constant, hardness, elastic modulus and carbon content of the manufactured insulating film were measured. The results are shown in Table 2.

It is a figure which shows the problem which may generate | occur | produce when forming a porous thin film with a prior art. It is a figure which shows the structure of the insulating film formed by this invention.

Claims (21)

One or more molecular polyhedral silsesquioxanes represented by the following chemical formula 2 are used alone, or one or more molecular polyhedral silsesquioxanes selected from the group consisting of compounds represented by the following chemical formulas 3, 4, 5 and 6 A siloxane-based resin produced by mixing with a monomer and subjected to condensation polymerization in the presence of water and an acid catalyst or a base catalyst in an organic solvent.
Wherein R is a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkynyl group, an aryl group or an alkoxy group, or -OSIR ₁ r ₂ r ₃ , r ₁ , r ₂ and r ₃ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkynyl group, an aryl group, or an alkoxy group, and the plurality of Rs are different from each other. And at least one of the R is a hydrolyzable functional group, and n is 10, 12, 14 or 16.)
(Wherein R ₁ is a hydrogen atom, a C ₁ -C ₃ alkyl group or a C ₆ -C ₁₅ aryl group, R ₂ is a hydrogen atom, a C ₁ -C ₁₀ alkyl group or SiX ₁ X ₂ X a _{3 (here,} a X _1, X 2, _{X 3} are each independently a hydrogen _atom, C 1 -C ₃ alkyl _group, an alkoxy group or a halogen atom C 1 _{-C 10,} at least one It is a hydrolyzable functional group), p is an integer of 3-8.)
(In the formula, R ₁ is a hydrogen atom, a C _{1 to} C ₃ alkyl group or a C _{6 to} C ₁₅ aryl group, and X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, C _{1 to} C 3 ₃ alkyl _group, an alkoxy group or a halogen atom C 1 _{-C 10,} at least one is a hydrolyzable functional group, m is an integer of 0, p is an integer of 3-8. )
(Wherein X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, a C _{1 to} C ₃ alkyl group, a C _{1 to} C ₁₀ alkoxy group or a halogen atom, at least one of which can be hydrolyzed) M is a direct bond, a C _{1 to} C ₁₀ alkylene group, or a C _{6 to} C ₁₅ arylene group.)
(In the formula, R ₁ is a hydrogen atom, a C ₁ -C ₃ alkyl group, a halogen group, or a C ₆ -C ₁₅ aryl group, and R ₂ is a hydrogen atom, a C ₁ -C ₃ alkyl group or C _6. an aryl group -C _15, at least one of _{R 1} and oR ₂ is a hydrolyzable functional group, n is an integer of 0-3.)   The acid catalyst is hydrochloric acid, nitric acid, benzenesulfonic acid, oxalic acid, formic acid or a mixture thereof, and the base catalyst is potassium hydroxide, sodium hydroxide, triethylamine, sodium bicarbonate, pyridine or a mixture thereof. The siloxane-based resin according to claim 1. 2. The siloxane-based resin according to claim 1, wherein the molar ratio of all monomers to the acid catalyst or base catalyst used is 1: 1 × 10 ⁻⁵ to 1:10.   The siloxane-based resin according to claim 1, wherein the molar ratio of all monomers to water used is 1: 1 to 1: 100.   The siloxane-based resin according to claim 1, wherein the polymerization reaction is performed at a temperature of 0 to 200 ° C. for 0.1 to 100 hours.   The organic solvent is an aliphatic hydrocarbon solvent that is hexane or heptane; an aromatic hydrocarbon solvent that is anisole, mesitylene, xylene, or benzene; a ketone system that is methyl isobutyl ketone, 1-methyl-2-pyrrolidinone, cyclohexanone, or acetone Solvent; ether solvent which is tetrahydrofuran or isopropyl ether; acetate solvent which is ethyl acetate, butyl acetate or propylene glycol methyl ether acetate; alcohol solvent which is isopropyl alcohol or butyl alcohol; amide solvent which is dimethylacetamide or dimethylformamide 2. A siloxane-based resin according to claim 1, which is a silicon-based solvent; or a mixture of the solvents.   The siloxane-based resin according to claim 1, wherein the siloxane-based resin has a weight average molecular weight of 1,000 to 300,000.   An insulating film forming composition comprising the siloxane-based resin according to claim 1 and an organic solvent.   The solvent is an aliphatic hydrocarbon solvent that is hexane or heptane; an aromatic hydrocarbon solvent that is anisole, mesitylene, xylene, or benzene; a ketone solvent that is methyl isobutyl ketone, 1-methyl-2-pyrrolidinone, cyclohexanone, or acetone An ether solvent that is tetrahydrofuran or isopropyl ether; an acetate solvent that is ethyl acetate, butyl acetate, or propylene glycol methyl ether acetate; an alcohol solvent that is isopropyl alcohol or butyl alcohol; an amide solvent that is dimethylacetamide or dimethylformamide; The composition for forming an insulating film according to claim 8, wherein the composition is a silicon-based solvent; or a mixture of the solvents.   The insulating film forming composition is further selected from the group consisting of cyclodextrin, polycaprolactone, Brij surfactant, polyethylene glycol-polypropylene glycol-polyethylene glycol ternary block copolymer surfactant and derivatives thereof. The composition for forming an insulating film according to claim 8, further comprising a pore forming substance. An insulating film forming composition comprising at least one molecular polyhedral silsesquioxane represented by the following chemical formula 2, a thermally stable siloxane precursor, and a solvent for dissolving them.
Wherein R is a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkynyl group, an aryl group or an alkoxy group, or -OSIR ₁ r ₂ r ₃ , r ₁ , r ₂ and r ₃ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkynyl group, an aryl group, or an alkoxy group, and the plurality of Rs are different from each other. And at least one of the R is a hydrolyzable functional group, and n is 10, 12, 14 or 16.) The thermally stable siloxane precursor may be prepared by mixing one or more monomers selected from the group consisting of compounds represented by chemical formulas 3, 4, 5 and 6 and mixing water and an acid catalyst in an organic solvent. The composition for forming an insulating film according to claim 11, wherein the composition is produced by condensation polymerization in the presence of a base catalyst.
(Wherein R ₁ is a hydrogen atom, a C ₁ -C ₃ alkyl group or a C ₆ -C ₁₅ aryl group, R ₂ is a hydrogen atom, a C ₁ -C ₁₀ alkyl group or SiX ₁ X ₂ X a _{3 (here,} a X _1, X 2, _{X 3} are each independently a hydrogen _atom, C 1 -C ₃ alkyl _group, an alkoxy group or a halogen atom C 1 _{-C 10,} at least one It is a hydrolyzable functional group), p is an integer of 3-8.)
(In the formula, R ₁ is a hydrogen atom, a C _{1 to} C ₃ alkyl group or a C _{6 to} C ₁₅ aryl group, and X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, C _{1 to} C 3 ₃ alkyl _group, an alkoxy group or a halogen atom C 1 _{-C 10,} at least one is a hydrolyzable functional group, m is an integer of 0, p is an integer of 3-8. )
(Wherein X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, a C _{1 to} C ₃ alkyl group, a C _{1 to} C ₁₀ alkoxy group or a halogen atom, at least one of which can be hydrolyzed) M is a direct bond, a C _{1 to} C ₁₀ alkylene group, or a C _{6 to} C ₁₅ arylene group.)
(In the formula, R ₁ is a hydrogen atom, a C ₁ -C ₃ alkyl group, a halogen group, or a C ₆ -C ₁₅ aryl group, and R ₂ is a hydrogen atom, a C ₁ -C ₃ alkyl group or C _6. an aryl group -C _15, at least one of _{R 1} and oR ₂ is a hydrolyzable functional group, n is an integer of 0-3.)   The insulating film forming composition is further selected from the group consisting of cyclodextrin, polycaprolactone, Brij surfactant, polyethylene glycol-polypropylene glycol-polyethylene glycol ternary block copolymer surfactant, and derivatives thereof. The composition for forming an insulating film according to claim 11, further comprising a pore forming substance.   The insulation according to any one of claims 11 to 13, wherein the molecular polyhedral silsesquioxane is contained in an amount of 0.1 to 99.9 mass% with respect to a total solid content in the composition. Film forming composition.   The solvent is an aliphatic hydrocarbon solvent that is hexane or heptane; an aromatic hydrocarbon solvent that is anisole, mesitylene, xylene, or benzene; a ketone system that is methyl isobutyl ketone, 1-methyl-2-pyrrolidinone, cyclohexanone, or acetone Solvent; ether solvent which is tetrahydrofuran or isopropyl ether; acetate solvent which is ethyl acetate, butyl acetate or propylene glycol methyl ether acetate; alcohol solvent which is isopropyl alcohol or butyl alcohol; amide solvent which is dimethylacetamide or dimethylformamide The composition for forming an insulating film according to claim 11, wherein the composition is a silicon-based solvent; or a mixture of the solvents.   The composition for forming an insulating film according to any one of claims 11 to 13, wherein the solid content of the composition is 5 to 70 mass% with respect to the entire composition.   12. A method for forming a semiconductor interlayer insulating film, comprising the steps of: producing the composition according to claim 8; and coating the composition on a substrate and thermally curing the composition.   The insulating film forming composition is further selected from the group consisting of cyclodextrin, polycaprolactone, Brij surfactant, polyethylene glycol-polypropylene glycol-polyethylene glycol ternary block copolymer surfactant, and derivatives thereof. 18. The method for forming a semiconductor interlayer insulating film according to claim 17, further comprising a pore forming substance.   18. The method of forming a semiconductor interlayer insulating film according to claim 17, wherein the coating is performed by spin coating, dip coating, spray coating, flow coating, or screen printing.   The method of forming a semiconductor interlayer insulating film according to claim 17, wherein the thermosetting is performed at a temperature of 150 ° C. to 600 ° C. for 1 to 180 minutes.   A semiconductor interlayer insulating film formed by the method of claim 17.